1. Field of the Invention
This invention pertains generally to the field of vehicle display units that present navigation information to the user of a vehicle such as the pilot of an aircraft.
2. Description of the Related Art
With an increased presence of fixed electronic flight displays installed in aircraft and portable electronic flight displays carried by pilots (e.g., electronic flight bags, portable tablets, etc. . . . ), the use of paper charts is being replaced with the use of electronic charts that are viewable on screens of electronic displays. Although paper charts contain an abundance of information, the amount of information viewable to a pilot is limited by the screen size of the display.
When a pilot wishes to form a clear mental image of present and future navigation needs, he or she might spend a significant amount of effort switching between charts to piece together bits of navigation information that is presented on one chart but not another. For example, when a pilot transitions from low altitude flight to high altitude flight or vice versa, he or she will likely have to switch charts; that is, when transitioning from a departure phase of flight or to an arrival phase of flight, the act of switching between charts can cause an undesirable increase to the pilot's workload and create an unsafe flying condition by distracting the pilot's attention.
Besides flight charts, the advent of the Flight Management System (“FMS”) allows the pilot to enter an approved flight plan using navigation information stored in an electronic database; one common database used by the aviation industry conforms to ARINC Specification 424 (“CARING 424”), an industry standard published by Aeronautical Radio, Incorporated (“ARINC”). ARINC 424 provides a standardized format of navigation information stored in standard electronic records and fields within each record. Because ARINC 424 standardizes the storage of navigation information, navigation records corresponding to information of an approved flight plan may be retrieved from the ARINC 424 database and used to generate navigation information related to the flight plan that may be presented on, for example, a navigation display (“ND”) of an Electronic Flight Instrument System (“EFIS”).
When a flight plan and other navigation information are presented on the ND of an EFIS from data retrieved from an ARINC 424 database, navigation information printed on a paper chart or published to an electronic chart might be omitted; that is, navigation information appearing on the navigation chart might not be visually presented on the ND. Moreover, the navigation information presented on the ND might not look like the navigation information presented in a navigation chart; that is, the visual appearances of navigation information presented on the ND may differ from those appearing on a navigation chart.